In this paper, the first-order shear deformation theory is used to derive theoretical formulationsillustrating the Nonlinear dynamic response of functionally graded porous plates under thermal and mechanicalloadings supported by Pasternak’ s model of the elastic foundation. Two types of porosity including evenlydistributed porosities (Porosity-I) and unevenly distributed porosities (Porosity-II) are assumed as effectiveproperties of FGM plates such as Young’ s modulus, the coefficient of thermal expansion, and density. The straindisplacementformulations using Von Karman geometrical Nonlinearity and general Hooke’ s law are used to obtainconstitutive relations. Airy stress functions with full motion equations which is employed to shorten the number ofgoverning equations along with the boundary and initial conditions lead to a system of differential equations of theNonlinear dynamic response of porous FGM plates. Considering linear parts of these equations, natural frequenciesof porous FGM plates are determined. By employing Runge-Kutta method, the numerical results illustrate theinfluence of geometrical configurations, volume faction index, porosity, elastic foundations, and mechanical as wellas thermal loads on the Nonlinear dynamic response of the plates. Good agreements are obtained in comparisonwith other results in the literature.